Earthworms comprise a group of invertebrates that live in the ground, eat decomposing organic material and produce a rich earthy substance referred to as castings. More technically, the worms are terrestrial annelid worms that are any of a family of numerous widely distributed hermaphroditic worms that move through the soil by means of state. Of these several varieties, the red worm has been found to be a hearty, rapidly multiplying organism capable of eating significant amounts of decomposing organic material.
Worm castings have been known as being very beneficial to promote plant growth for more than 100 years. Research by Ohio State University testing for the recommended application rate of worm castings for highest growth improvement recommended a 10%–20% mix. The rule given by Ohio State University to achieve these percentages was that a ½ inch layer worked into the soil will provide a 10% ratio and a 1-inch layer worked into the soil will provide a 20% ratio.
In order to make worm castings economically and industrially beneficial concentrating the beneficial properties is indicated. Traditionally, this has been done by washing the worm castings using a variety of different methods (worm tea). However, simple washing has not been found to yield the most benefit from the castings. Inclusion of solids to the worm tea produces vermicompost, which has additional benefits provided by the solids. Therefore, there is a present and continuing need for new and improved methods for producing concentrated vermicompost.